KR20000062299A - Electric actuator - Google Patents

Abstract

The electric actuator of the present invention surrounds the main actuator body 12, the drive unit 16, the transfer screw shaft 32 and the transfer screw shaft 32 for transmitting the rotational driving force of the rotary drive source 14, and is coupled from the outside. And the moving member 40 moving along the axial direction in accordance with the coupling action between the male screw 36 and the female screw 42, and the sensor-equipped long grooves 24a and 24b provided at the side portions of the main actuator body 12, and the sensor. The sensor 25 provided in the predetermined part in the attachment groove 24a, 24b is provided.

Description

Electric Actuator {ELECTRIC ACTUATOR}

Up to now electric actuators have been used, for example, as a means of transporting workpieces. As shown in Figs. 9 and 10, this electric actuator is composed of an elongated frame 1 having an opening acting as a main actuator body and a block-shaped electric motor 2 fixed to one end of the frame 1. do. This electric actuator has a motor shaft of a ball screw 3 and an electric motor 2 which are coaxially connected to each other using a coupling member (not shown). The movable member 4 is fixed to the nut member not shown in combination with the ball screw 3.

Long side grooves 5a and 5b for attaching a sensor are formed on the side of the frame 1 along the longitudinal direction of the frame 1. This sensor 6 is provided in predetermined portions of the long grooves 5a and 5b. The conductive wire 7 electrically connected to the sensor 6 enters the long grooves 5a and 5b. One end of the lead wire 7 is connected to an external device such as a controller. The detection signal detected by the sensor 6 is input to the external device.

The opening of the frame 1 is closed with a cover plate 8. Slits 9a and 9b are formed in the remaining part not blocked by the cover plate 8 (see FIG. 10). These slits 9a and 9b communicate with the outside and are formed along the axial direction of the frame 1.

In this structure, the nut member engaged with the ball screw 3 is moved linearly along the slits 9a and 9b according to the driving action of the electric motor 2. Thus, the movable member 4 fixed to the nut member is moved integrally.

However, in the case of the electric actuator according to the related art described above, slits 9a and 9b serving as spaces for moving the nut member are formed in the opening of the frame 1. Therefore, dust or the like enters the inside of the frame 1 from the outside through the slits 9a and 9b and sticks to the ball screw 3. As a result, the driving force transfer function of the ball screw 3 decreases, and the inconvenience that the movable member 4 cannot perform smooth reciprocating operation | movement arises.

In addition, for example, when performing any repair work, the following inconvenience occurs. That is, the operator comes into contact with the conductive wires 7 exposed to the outside from the long grooves 5a and 5b, whereby the conductive wires are caught. As a result, the position of the sensor 6 provided in the predetermined part of the long grooves 5a and 5b deviates.

The present invention relates to an electric actuator which transmits the rotational driving force of the rotational drive source by the driving force transmission means to the moving member and functions as a conveying mechanism of the workpiece, for example.

1 is a front view showing an electric actuator according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view taken along line II-II shown in FIG. 1; FIG.

3 is a cross-sectional view taken along the line III-III shown in FIG.

FIG. 4 is a longitudinal sectional view showing a drive section constituting the electric actuator shown in FIG. 1; FIG.

5 is a perspective view showing a cover member constituting the electric actuator shown in FIG.

6 is a sectional view showing an electric actuator according to another embodiment of the present invention.

Fig. 7 is a schematic diagram showing a state in which the electric actuator shown in Fig. 6 is assembled to another member.

8 is a schematic view showing a state in which the electric actuator shown in FIG. 6 is assembled to another member.

9 is an exploded perspective view showing an electric actuator according to the prior art.

10 is a cross-sectional view taken along the line X-X shown in FIG. 9;

An object of the present invention is to prevent the intrusion of dust and the like into the main actuator body to avoid the reduction of the driving force transmission function, and to prevent any deviation of the sensor that can be caused by the stretching action made in the conductor To provide.

According to the present invention, the rotary driving force transmitting member operating in accordance with the driving action of the rotary driving source is doublely surrounded by the moving member and the main actuator body.

Further, according to the present invention, the sensor is attached to a predetermined portion in the long groove provided on the side of the main actuator body. This sensor detects the magnetic field of the permanent magnet moving integrally with the moving member. Therefore, the movement amount of the movable member can be detected.

1 and 2, reference numeral 10 denotes an electric actuator according to an embodiment of the present invention. The electric actuator 10 has a hollow parallelepiped shape and a main actuator body 12 having a through-hole formed along the axial direction, and is formed to be substantially coplanar with the side surface of the main actuator body 12 so as to rotate the driving source. And a drive unit 16 aligned with 14 (see Fig. 4).

The main actuator body 12 has a hollow parallelepiped shape, each having a first main body 18 and a second main body 20 formed to have side surfaces, and a head cover connected to one end of the first main body 18. It consists of 22. On each of the two sides of the first body 18, the second body 20, and the head cover 22, a pair of sensor-equipped long grooves 24a and 24b having an arc structure are formed substantially parallel to each other ( 3). The cylindrical sensor 25 is provided in the predetermined part of the sensor attachment long groove 24a, 24b (refer FIG. 3). The position of a piston can be detected by detecting the magnetic field of the permanent magnet provided so that it may move integrally with a piston as mentioned later.

As shown in FIG. 2, the second main body 20 connected to the driving unit 16 is coaxial to the driving shaft 30 of the rotation drive source 14 by the connecting member 26 and the lock nut 28. Transfer screw shaft (rotary drive force transmitting member) 32 is connected to be installed. The conveying screw shaft 32 is rotatably supported by the first bearing member 34 provided with the ball bearing 33. Male screws 36 are formed in predetermined portions on the outer circumferential surface of the feed screw shaft 32. Transfer screw shaft 32 has a moving member 40 having a piston 38 is coupled to the outside. The female screw 42 formed on the inner circumferential surface of the moving member 40 is coupled to the male screw 36 formed on the outer circumferential surface of the transfer screw shaft 32. Thus, the moving member 40 is moved in the direction indicated by the arrow X ₁ or X ₂ in accordance with the engagement action of the transfer screw shaft 32.

It is advantageous that the first body 18 and the piston 38 can be manufactured inexpensively when they are formed by aluminum extrusion or resin molding.

The piston 38 sliding along the hole 44 of the first body 18 is installed at one end of the cylindrical moving member 40. The permanent magnet 46 is coupled to the piston 38 by an annular groove. Splines 48 are formed on the outer circumferential surface of the piston 38. The spline groove 50 corresponding to the spline 48 is formed in the inner side wall surface of the hole 44 of the 1st main body 18 by which the piston 38 slides (refer FIG. 3). As the piston 38 moves along the hole 44 according to the guide action of the spline groove 50, the rotation preventing function of the moving member 40 is achieved.

The sensor 25 installed in the sensor mounting long grooves 24a and 24b detects the magnetic field of the permanent magnet 46 which is integrally moved with the piston 38. Therefore, the position of the piston 38 can be detected. On both ends of the first body 18, a pair of damper members 52a and 52b are arranged to adjust the displacement of the distal position and to reduce the impact upon contact with the piston 38, respectively. The spacer 54 is interposed between the first bearing member 34 and the damper member 52b.

The head cover 22 includes a rod packing 56 surrounding the moving member 40 and a moving member 40 to prevent dust or the like from entering the hole 44 of the first body 18. A guiding bush 58 is installed when moving in the direction of arrow X ₁ or X ₂ .

As shown in FIG. 5, the rectangular cover member 60 is detachably attached to the side surface of the second body 20 by a screw 62. The cover member 60 is provided with a pair of conductive wire outlets 66a and 66b for cooperating with the sensor mounting long grooves 24a and 24b to externally guide the conductive wires from the sensor 25.

That is, the cover member 60 is provided with a pair of first holes 68a and 68b extending coaxially with the sensor mounting long grooves 24a and 24b. The cover member 60 is also provided with a pair of second holes 70a and 70b which are bent outward at a predetermined angle from the first holes 68a and 68b. Fixing tabs 71a and 71b having an acute angle structure for fixing the conductive wire 64 are formed in the outlets 66a and 66b, respectively.

In this embodiment, the sensor 25 is provided at a predetermined portion of the sensor mounting long grooves 24a and 24b of the main actuator body 12. The conducting wire 64 guided inside the long grooves 24a and 24b for attaching the sensor is bent along the first holes 68a and 68b and the second holes 70a and 70b. The conductive wire 64 is fixed to a predetermined portion by using the fixing tabs 71a and 71b provided at the conductive wire outlets 66a and 66b. Thus, the conductive wire 64 is fixed by the cover member 60.

As shown in FIG. 4, the drive part 16 is comprised from the rotation drive source 14 and the brake mechanism 72, and is accommodated in the housing 73. As shown in FIG. The drive shaft 30 of the rotation drive source 14 is rotatably supported by the second bearing member 74 and the third bearing member 76 which are separated from each other at predetermined intervals. The distal end of the drive shaft 30 extends to the brake mechanism 72. The rotary drive source 14 includes a rotor 78 fixed to the drive shaft 30 to rotate integrally with the drive shaft 30, and a stator 80 fixed to the housing 73.

The brake mechanism 72 includes a casing 84 in which the electromagnet coils 82 are aligned, and a braking pad 86 that is provided outside the casing 84 and rotates integrally with the drive shaft 30. A pair of intervening plates 88a and 88b are provided between which the braking pads 86 are fitted. The first intervening plate 88a is installed to be pressed toward the second intervening plate 90 by the elastic force of the spring member 90 fixed to the recessed portion of the casing 84. Therefore, the braking pad 86 fixes the both sides of the braking pad 86 by interposing a pair of intervening plates 88a and 88b according to the action of the elastic force of the spring member 90. Thus, a braking action is made to stop the rotation of the drive shaft 30. A gap 89 having a predetermined gap is formed between the casing 84 surrounding the electromagnet coil 82 and the first intervening plate 88a.

The first intervening plate 88a to which the pressing force is applied by the spring member 90 is provided to be movable along the axial direction of the drive shaft 30. When power is applied to the electromagnet coil 82 to be in an ON state from the state shown in FIG. 4, the first interplate 88a is pulled toward the electromagnet coil 82 while overcoming the elastic force of the spring member 90. As a result, the braking action is lost and the drive shaft 30 is rotated in the predetermined direction.

The electric actuator 10 according to the embodiment of the present invention is basically configured as described above. Next, the operation, action and effect will be described.

First, a pair of sensors 25 are installed at predetermined portions in the long grooves 24a and 24b for sensor attachment. Thereafter, the conductive wire 64 connected to the sensor 25 is guided from the inside along the long grooves 24a and 24b for attaching the sensor to the first holes 68a and 68b and the second holes 70a and 70b of the cover member 60. Is installed along. This conductor 64 is guided from the outside from the conductor outlets 66a and 66b.

In this structure, the conductive wire 64 is bent by the second holes 70a and 70b inclined at a predetermined angle in the cover member 60. This conductive wire 64 is fixed by fixing tabs 71a and 71b provided at the conductive wire outlets 66a and 66b. Therefore, as will be described later, even if the operator accidentally contacts the conductor 64 and the conductor 64 is caught, the sensor 25 is fixed by the cover member 60, so that the sensor 25 Deviation of the sensor position which may be caused by the stretching action made in 64 can be prevented.

Then, when a power source (not shown) acts, the rotary drive source 14 rotates. The rotational driving force of the rotational drive source 14 is transmitted by the connecting member 26 to the transfer screw 32 which is coaxially connected thereto. The moving member 40 is moved by the arrow X ₁ or X ₂ according to the coupling action between the male screw 36 of the transfer screw shaft 32 and the female screw 36 formed on the inner circumferential surface of the moving member 40. It is moved in the direction shown.

During this process, the spline 48 formed on the outer circumferential surface of the piston 38 serves to prevent rotation of the moving member 40. In addition, the guide action is exhibited by the bush 58 provided in the head cover 22 and the first bearing member 34 provided in the second body 20, respectively.

The piston 38 comes into contact with one of the damper members 52a or 52b during the moving process in which the moving member 40 moves in the direction of arrow X ₁ (X ₂ ) according to the engagement action of the feed screw shaft 32. do. Therefore, the end position of the movement is limited, and the shock during connection is absorbed.

On the other hand, by rotating the rotary drive source 14 in the opposite direction using the switching means (not shown), the moving member 40 moves in the direction of arrow X ₂ (X ₁ ) to return to the original position.

In the present embodiment, the sensor 25 is conveniently installed at predetermined portions of the sensor mounting long grooves 24a and 24b formed on the side surface of the main actuator body 12. Therefore, the displacement amount of the movable member 40 can be detected.

In this embodiment, the transfer screw shaft 32 which is coaxially connected to the drive shaft 30 of the rotary drive source 14 by the connecting member 26 is a moving member (3) externally coupled to the transfer screw shaft (32). 40) and the main actuator body 12 is doublely surrounded. Therefore, it is possible to prevent dust and the like from sticking to the conveying screw shaft 32.

Therefore, it is possible to improve durability by avoiding an increase in sliding resistance of the transfer screw shaft 32, which may be caused by dust and the like attached to the transfer screw shaft 32. In addition, the rotational driving force of the rotational drive source 14 may be smoothly transmitted to the moving member 40.

Further, in the present embodiment, the conductive wire 64 is inserted along the first hole 68a and the second hole 70a, 70b provided in the cover member 60, and the portions of the conductive wire 64 are covered with the cover member ( 60). Thus, for example, if the operator comes into contact with the conductive wire 64 exposed to the outside from the long grooves 24a and 24b for attaching the sensor and the conductive wire 64 is caught when performing repair work, the portion of the conductive wire 64 is covered by the cover member. Since it is fixed by 60, the positional deviation of the sensor 25 which may be caused by the elastic action which is performed in a conducting wire can be avoided.

In this embodiment of the present invention, the conductive wire 64 is guided to the outside through the conductive wire outlets 66a and 66b provided in the cover member 60, and the conductive wire 64 is prevented from contacting the driving unit 16. Adopting a structure in which the damage to the conductive wire 64, which may be caused by the release of heat generated during the driving operation of 16, can be avoided.

Next, an electric actuator 10a according to another embodiment of the present invention is shown in FIG. This electric actuator 10a differs in the following points. That is, this electric actuator 10a does not have rotation prevention means, such as the spline 48 and the spline groove 50 as shown in FIG. The cross-sectional structure of the outer circumferential surface of the piston 38 and the hole 44 of the first body 18 is formed to be circular. Another member (described later) provided externally in an additional manner is used to show the anti-rotation action on the moving member 40. It should be noted that the same components as those of the electric actuator 10 shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

A detailed example in which the electric actuator 10a according to another embodiment is used is shown in FIG. 7, for example. A pair of struts 94a and 94b are fixed to the substrate 92. A pin member 96 supported between the pair of struts 94a and 94b is used as the center of rotation to rotatably support the electric actuator 10a in the direction indicated by the arrow. Coupling member 98 connected to one end of moving member 40 is used to support flat plate 100. In this embodiment, the moving member 40 moves back and forth in the direction indicated by the arrow according to the driving action of the electric actuator 10a. Thus, using the point A as the center of rotation, the plate 100 can be rotated by a predetermined angle.

Alternatively, as shown in FIG. 8, a support block 102 is used to secure the electric actuator 10a to the substrate 104 generally parallel. The flange 108 is fixed to the linear guide 106 fixed on the substrate 104 by screws. This flange 108 is connected to one end of the moving member 40. As a result, the movable member 40 and the flange 108 are integrally moved in accordance with the guiding action of the linear guide rail 110.

As described above, in the case of the electric actuator 10a according to the other embodiment, the moving member 40 is prevented from rotating by another additional member such as a guide member. Therefore, it is not necessary to provide the rotation preventing means for the moving member 40. Therefore, the above structure is advantageous in that the processing operation can be simplified and the manufacturing cost can be reduced.

Sharp edges or rough areas that occur during the manufacturing step are optionally attached to the outer circumferential surface of the transfer screw shaft 32. Such sharp edges or rough areas may cause damage to the coupling portion between the transfer screw shaft 32 and the moving member 40, so that a smooth rotation operation may be disturbed.

In this case, after the transfer screw shaft 32 is processed, the threaded portion of the transfer screw shaft 32 is subjected to, for example, chemical polishing, electropolishing or short peening. Therefore, sharp edges, rough areas, process scratches, and the like can be removed. In addition, surface treatments such as tuftride and electroless plating may be applied to the outer surface of the transfer screw shaft 32. This treatment is advantageous in that the sliding performance can be further improved.

According to the present invention, the rotational driving force transmitting member is doublely surrounded by the moving member and the main actuator body. Therefore, it is possible to prevent dust and the like from sticking to the rotational driving force transmission member.

Therefore, durability can be improved by avoiding an increase in sliding resistance of the rotational drive force transmission member, which can be caused by dust and the like adhering to the rotational drive force transmission member. In addition, it is possible to smoothly transfer the rotational driving force of the rotational drive source to the moving member.

In addition, the conducting wire is fixed by the cover member. Therefore, it is possible to avoid the dislocation of the sensor which may be caused by the stretching action occurring in the conductor.

Claims (9)

A cylindrical main actuator body 12, A rotation drive source 14 disposed on the drive unit 16 disposed next to the main actuator body 12; In order to transfer the rotational driving force of the rotary drive source 14, and the rotational drive force transmission member 32 is connected coaxially to the drive shaft 30 of the rotary drive source 14, Surrounding the rotational driving force transmission member 32, it is composed of a movable member 40 movable along the axial direction of the main actuator body 12 in accordance with the coupling action with the rotational driving force transmission member 32, The rotational driving force transmission member is composed of a transfer screw shaft 32, the movable member 40 is a male screw 36 formed on the outer circumference of the transfer screw shaft 32 and a female screw formed on the inner peripheral surface of the movable member 40 An electric actuator, which is movable along the axial direction in accordance with the engaging action by (42). 2. The electric actuator as claimed in claim 1, wherein the drive unit (16) is provided with a brake mechanism (72) for braking the rotational force of the drive shaft (30) of the rotary drive source (14). 2. The permanent magnet of claim 1, wherein long side grooves 24a and 24b are formed at side portions of the main actuator body 12, and predetermined portions of the long grooves 24a and 24b are integrally movable with the movable member 40. An electric actuator, characterized in that a sensor (25) is provided for detecting the magnetic field of (46). 4. The fixing member (60) according to claim 3, wherein a side surface of the main actuator body (12) is provided with a fixing member (60) which is used to fix the conductor of the sensor (25) disposed along the long grooves (24a, 24b). Electric actuator. 5. The fixing member of claim 4, wherein the fixing member comprises a cover member (60), the cover member (60) having first holes (68a, 68b) communicating with the long grooves (24a, 24b), and the first hole. Second holes 70a and 70b which are inclined outwardly by a predetermined angle from 68a and 68b, and conductive wire outlets 66a and 66b communicating with the second holes 70a and 70b are formed. 66a, 66b) is provided with a sharp fixing tab (71a, 71b) for fixing the conductive wire (64). The piston 38 of claim 1, wherein one end of the movable member 40 is provided with a piston 38 which is integrally movable with the movable member 40 along the hole 44 of the main actuator body 12. The piston (38) is an electric actuator, characterized in that the spline (48) is formed to prevent the rotation of the moving member (40). 7. The pair of damper members (52a) according to claim 6, wherein the holes (44) of the main actuator body (12) are used to limit the amount of displacement of the movable member (40) upon contact with the piston (38). 52b), characterized in that the electric actuator. 3. The brake mechanism (72) according to claim 2, wherein the brake mechanism (72) rotates integrally with the driving shaft (30) of the rotary drive source (14) and the spring member (90) under the action of the elastic force. A pair of intervening plates 88a and 88b interposed between the braking pads 86 and one of the intervening plates 88a or 88b against the elastic force of the spring member 90 in accordance with the application of a power source are applied to and braked. And an electromagnet coil (82) for damping the action. The method of claim 1, wherein one end of the main actuator body 12 is used to surround the outer circumferential surface of the moving member 40 to prevent dust or the like from entering the hole 44 of the main actuator body 12. An electric actuator, characterized in that the sealing member 56 is provided.